I’ve shared how too little sleep causes a variety of medical issues. It’s logical to think that lots more sleep may sound like the answer. Or better yet, if you can’t sleep enough during the week, get 10-12 hours on weekends. But it’s been shown that sleeping in excess of 9 hours per night can be just as damaging to your sleep cycles and health.
The negative health effects of too little sleep are well-documented, but what happens from sleeping too much is less clear. The National Sleep Foundation recommends that the average adult get 7-9 hours of sleep. But what if your body craves more sleep, can you get too much? A growing body of research say yes, leading to a variety of health concerns:
One concerning problem linked with long sleep is cardiovascular disease. Researchers from the Chicago School of Medicine found that people who sleep more than 8 hours per night are twice as likely to have angina (chest pain) and 10 percent more likely to have coronary heart disease. The large Nurses Health Study which involved over 71,000 middle-aged women, also found connections between sleep length and heart health. Compared to normal eight hour sleepers, women sleeping nine to 11 hours per night were 38% more likely to have coronary heart disease.
Higher Stroke Risk:
A recent study from University of Cambridge looked at data from around 9,700 Europeans over a period of 11 years. People who slept over eight hours were 46% more likely to have had a stroke during the study period after adjusting for comorbid factors. People whose sleep duration had increased during the study had a four times higher risk of stroke than consistent sleepers, suggesting that longer sleep could be an important symptom or warning sign of stroke risk. Data from older NHANES surveys (The CDC’s National Health and Nutrition Examination Survey) also found a significant relationship was found between long sleep and stroke risk. People who slept more than eight hours had a 50% higher risk of stroke than people who slept six to eight hours. People who slept over eight hours and who also had daytime drowsiness had a 90% higher stroke risk compared to normal sleepers.
Increases Weight Gain:
Oversleeping has a powerful impact on how your body stores fat, and it’s ability to lose it. New research from the University of Glasgow has discovered that sleeping too long can make you gain as much weight – and potentially even more – than sleeping too little. Check back for our post this Wednesday for more info.
Increased Risk of Diabetes:
Our ability to process sugars, and impaired glucose tolerance is associated with insulin resistance and is a risk factor for type 2 diabetes and heart disease. A Canadian study looked at lifestyle habits of 276 people over six years, finding that people with long and short sleep duration were more likely to develop impaired glucose tolerance and diabetes during the time span compared to normal sleepers (20% versus 7%). This was even after adjusting for body mass. Long sleepers had double the risk of developing diabetes. Other studies suggest that too much (or too little) sleep can affect your blood glucose levels, regardless of your weight or activity level.
You know that feeling when you sleep in, only to wake up groggy and with a headache, almost like you have a hangover? Although that could be caused by poor sleep, it also could be one of the side effects of sleeping too much. The mechanism behind this isn’t understood that well. One hypothesis is that fluctuations in neurotransmitters during sleep may be a trigger for headaches. Another possibility is that when people sleep later in the morning, they may be sleeping past their normal breakfast or coffee time, and the headaches may be related to caffeine withdrawals, low blood sugar, or dehydration. The best sleep pattern to avoid this “weekend headache” is to get a consistent amount of sleep every night, and to go to bed and wake up at the same time each day.
One symptom of depression is oversleeping, so having untreated mental health problems could be one reason why you’ve had a hard time getting up. Studies have shown long sleep is significantly associated with frequent mental distress. Another study of twins found that long sleep actually activated genes related to depressive symptoms. One hypothesis is that long sleep duration is associated with decreased physical activity. Physical activity has been associated with reduced risk of depression by increasing levels of the neurotransmitters dopamine and serotonin, increasing release of endorphins, distracting from stressful stimuli, and improving self-esteem. On the other hand, people who are depressed may use sleep as an escape or coping mechanism, and so stay in bed longer.
A reduction in activity from spending too much time in bed can lead you to be more achy, especially if you have back problems. It probably has to do with lying in a position for an extended period of time, lack of movement while sleeping, or a bad mattress. You also might be suffering from poor sleep because of your pain, which again makes you want to sleep longer. But don’t give in, because more activity (under your doctor’s supervision) can help alleviate pain, leading to better quality sleep in a typical amount of time.
Chronic inflammation is linked with an increased risk of a host of chronic diseases such as diabetes, heart disease and Alzheimer’s. Getting too little or too much sleep can significantly contribute to inflammation. Inflammation is measured by levels of cytokines called C-reactive proteins, or CRP. One study compared CRP levels and sleep durations in a large group of adults and found that long sleepers had elevated levels of inflammatory markers. One study showed that CRP levels increased by 8% for each additional hour of sleep beyond the normal seven to eight hours per night, even when adjusting for factors like body mass, age and sleep apnea.
Along with headaches, you may experience a “foggy brain” feeling if you get too much sleep. A Harvard study showed that older women who slept more than nine hours had worse cognition, the equivalent of aging almost two years! Other research showed a connection between long sleep and later dementia. Since sleep duration is linked with so many other factors that can also influence cognition, it’s likely that there are both direct and indirect effects of sleep duration on cognition. Plus, the disrupted sleep that many long sleepers have may cause decreased brain function. Oversleeping might also be a marker of underlying circadian disruptions or health problems that could lead to structural brain changes and poor cognitive function.
Feeling Jet Lagged:
Sleeping too much may throw off your circadian rhythms, just as if you’ve been on a long plane trip. These rhythms are controlled by our “internal clock,” the part of our brain that responds to light and dark signals. When light hits the eye, it signals to the internal clock that it is time to be awake, which will then begin a cascade of other processes, control of hormones and body temperature, that play a role in making us feel awake and allow us to function at our best throughout the day. Oversleeping and other circadian disruptions, like jet lag or shift work, change these light cues and put us in conflict with our normal daily rhythm.
A study of Korean women undergoing in vitro fertilization therapy found that women who slept seven to eight hours had the best chances of conceiving. The moderate sleepers had the highest pregnancy rates (53%) compared to those sleeping six hours or less (46%) and those sleeping nine to eleven hours (43%). Study authors suggest sleep outside the normal range could be affecting hormones and circadian cycles, impairing fertility.
Higher All-Cause Mortality Risk:
In addition to (and perhaps as a result of) all of the other associated health issues like obesity, heart disease and stroke, longer-than-normal sleeping is also linked with a higher risk of death in general. Long sleep was also associated with numerous other conditions including obesity, multiple sclerosis, pulmonary disease, depression and poor immune function.
Of course, there is the chicken-and-egg question of whether oversleeping causes these type of harmful conditions, or whether certain illnesses cause oversleeping. Some studies indicate getting too much sleep may trigger certain problems while others show oversleeping to be a byproduct of co- occurring diseases or illnesses. This same research also notes that more healthy people may simply need less rest while unhealthy people tend to need more sleep. The field of sleep science is still looking into the cause and effect relationship between oversleeping and health, but until then, there are definitely several research proven habits and steps that can promote better quality sleep and a healthy sleep duration. Whether you’re an undersleeper or an oversleeper. These “healthy sleep hygiene” habits include:
1. If you’re taking any medication or supplement that causes excessive excitability or drowsiness, from caffeine to anti-histamines, consider stopping the medication or supplement or changing the timing of it.
2. Go out of your way to get exposure to large amounts of natural light in the morning (using proper sun protection, of course) and limit exposure to artificial light in the evening.
3. Keep any alarm clocks out of arm’s reach and consider getting a dawn sunlight emitting alarm clock, which can wake you with natural light rather than a blaring alarm.
4. Establish a sleep schedule and stick to it, even on the weekends. Oversleeping on Saturday and Sunday can inhibit your ability to re-establish a normal sleep cycle on the weekdays.
5. Shoot for approximately seven to nine hours of sleep a night and avoid excessive naps, especially in the later afternoon or early evening, as these naps may make it more difficult to fall asleep at night and result in oversleeping. The same goes for excessive caffeine and blue light exposure close to bedtime.
By now you probably realize that health is complex -if one part of the body system suffers, you’re likely to see consequences in other areas of your life. Getting the proper amount of sleep each night is necessary to face the world with your best foot forward. Sleep will help you on the road to good fitness, good eating and good health.